1 6556 94 TRANSGENERATIONAL EFFECTS OF POLYETHYLENE MICROPLASTIC FRAGMENTS CONTAINING BENZOPHENONE-3 ADDITIVE IN DAPHNIA MAGNA. MATERNAL EXPOSURE TO MICROPLASTICS (MPS) PLAYS AN IMPORTANT ROLE IN THE FITNESS OF UNEXPOSED PROGENY. IN THIS STUDY, THE TRANSGENERATIONAL EFFECTS OF POLYETHYLENE MP FRAGMENTS (17.35 +/- 5.50 MICROM) CONTAINING BENZOPHENONE-3 (BP-3; 2.85 +/- 0.16% W/W) ON CHRONIC TOXICITY (21 D) IN DAPHNIA MAGNA WERE INVESTIGATED ACROSS FOUR GENERATIONS. ONLY D. MAGNA IN THE F0 GENERATION WAS EXPOSED TO MP FRAGMENTS, MP/BP-3 FRAGMENTS, AND BP-3 LEACHATE TO IDENTIFY THE TRANSGENERATIONAL EFFECT IN THE F3 GENERATION. THE MORTALITY OF D. MAGNA INDUCED BY MP AND MP/BP-3 FRAGMENTS WAS RECOVERED IN THE F3 GENERATION, BUT SOMATIC GROWTH AND REPRODUCTION SIGNIFICANTLY DECREASED COMPARED TO THE CONTROL. ADDITIONALLY, REPRODUCTION OF D. MAGNA EXPOSED TO BP-3 LEACHATE SIGNIFICANTLY DECREASED IN THE F3 GENERATION. THESE FINDINGS CONFIRMED THE TRANSGENERATIONAL EFFECTS OF MP FRAGMENT AND BP-3 ADDITIVE ON D. MAGNA. PARTICULARLY, THE ADVERSE EFFECT ON D. MAGNA REPRODUCTION SEEMED TO BE CUMULATIVE ACROSS FOUR GENERATIONS FOR MP/BP-3 FRAGMENTS, WHILE IT WAS AN ACCLIMATION TREND FOR BP-3 LEACHATE. HOWEVER, THERE WAS NO SIGNIFICANT DIFFERENCE IN GLOBAL DNA METHYLATION IN D. MAGNA ACROSS FOUR GENERATIONS, THUS REQUIRING A GENE-SPECIFIC DNA METHYLATION STUDY TO IDENTIFY DIFFERENT EPIGENETIC TRANSGENERATIONAL INHERITANCE. 2022 2 6552 35 TRANSGENERATIONAL DNA METHYLATION CHANGES IN DAPHNIA MAGNA EXPOSED TO CHRONIC GAMMA IRRADIATION. OUR AIM WAS TO INVESTIGATE EPIGENETIC CHANGES IN DAPHNIA MAGNA AFTER A 25-DAY CHRONIC EXTERNAL GAMMA IRRADIATION (GENERATION F0 EXPOSED TO 6.5 MUGY.H(-1) OR 41.3 MGY.H(-1)) AND THEIR POTENTIAL INHERITANCE BY SUBSEQUENT RECOVERING GENERATIONS, NAMELY, F2 (EXPOSED AS GERMLINE CELLS IN F1 EMBRYOS) AND F3 (THE FIRST TRULY UNEXPOSED GENERATION). EFFECTS ON SURVIVAL, GROWTH, AND REPRODUCTION WERE OBSERVED AND DNA WAS EXTRACTED FOR WHOLE-GENOME BISULFITE SEQUENCING IN ALL GENERATIONS. RESULTS SHOWED EFFECTS ON REPRODUCTION IN F0 BUT NO EFFECT IN THE SUBSEQUENT GENERATIONS F1, F2, AND F3. IN CONTRAST, WE OBSERVED SIGNIFICANT METHYLATION CHANGES AT SPECIFIC CPG POSITIONS IN EVERY GENERATION INDEPENDENT OF DOSE RATE, WITH A MAJORITY OF HYPOMETHYLATION. SOME OF THESE CHANGES WERE SHARED BETWEEN DOSE RATES AND BETWEEN GENERATIONS. ASSOCIATED GENE FUNCTIONS INCLUDED GENE FAMILIES AND GENES THAT WERE PREVIOUSLY SHOWN TO PLAY ROLES DURING EXPOSURE TO IONIZING RADIATION. COMMON METHYLATION CHANGES DETECTED BETWEEN GENERATIONS F2 AND F3 CLEARLY SHOWED THAT EPIGENETIC MODIFICATIONS CAN BE TRANSMITTED TO UNEXPOSED GENERATIONS, MOST LIKELY THROUGH THE GERMLINE, WITH POTENTIAL IMPLICATIONS FOR ENVIRONMENTAL RISK. 2018 3 2484 34 EPIGENETIC, TRANSCRIPTIONAL AND PHENOTYPIC RESPONSES IN TWO GENERATIONS OF DAPHNIA MAGNA EXPOSED TO THE DNA METHYLATION INHIBITOR 5-AZACYTIDINE. THE WATER FLEA DAPHNIA MAGNA IS A KEYSTONE SPECIES IN FRESHWATER ECOSYSTEMS AND HAS BEEN WIDELY USED AS A MODEL ORGANISM IN ENVIRONMENTAL ECOTOXICOLOGY. THIS AQUATIC CRUSTACEAN IS SENSITIVE TO ENVIRONMENTAL STRESSORS AND DISPLAYS CONSIDERABLE PLASTICITY IN ADAPTING TO CHANGING ENVIRONMENTAL CONDITIONS. PART OF THIS PLASTICITY MAY BE DUE TO EPIGENETIC REGULATION OF GENE EXPRESSION, INCLUDING CHANGES TO DNA METHYLATION AND HISTONE MODIFICATIONS. BECAUSE OF THE GENERALLY HYPOMETHYLATED GENOME OF THIS SPECIES, WE HYPOTHESIZED THAT THE HISTONE CODE MAY HAVE AN ESSENTIAL ROLE IN THE EPIGENETIC CONTROL AND THAT HISTONE MODIFICATIONS MIGHT BE AN EARLY MARKER FOR STRESS. THIS STUDY AIMS TO CHARACTERIZE THE EPIGENETIC, TRANSCRIPTIONAL AND PHENOTYPIC RESPONSES AND THEIR CAUSAL LINKAGES IN DIRECTLY EXPOSED ADULT (F0) DAPHNIA AND PERITONEAL EXPOSED NEONATES (F1) AFTER A CHRONIC (7-DAY) EXPOSURE TO A SUBLETHAL CONCENTRATION (10 MG/L) OF 5-AZACYTIDINE, A WELL-STUDIED VERTEBRATE DNA METHYLATION INHIBITOR. EXPOSURE OF THE F0 GENERATION SIGNIFICANTLY REDUCED THE CUMULATIVE FECUNDITY, ACCOMPANIED WITH DIFFERENTIAL EXPRESSION OF GENES IN THE ONE-CARBON-CYCLE METABOLIC PATHWAY. IN THE EPIGENOME OF THE F0 GENERATION, A DECREASE IN GLOBAL DNA METHYLATION, BUT NO SIGNIFICANT CHANGES ON H3K4ME3 OR H3K27ME3, WERE OBSERVED. IN THE F1 OFFSPRING GENERATION, CHANGES IN GENE EXPRESSION, A SIGNIFICANT REDUCTION IN GLOBAL DNA METHYLATION AND CHANGES IN HISTONE MODIFICATIONS WERE IDENTIFIED. THE RESULTS INDICATE THAT EXPOSURE DURING ADULTHOOD MAY RESULT IN MORE PRONOUNCED EFFECTS ON EARLY DEVELOPMENT IN THE OFFSPRING GENERATION, THOUGH INTERPRETATION OF THE DATA SHOULD BE CAREFULLY DONE SINCE BOTH THE EXPOSURE REGIME AND DEVELOPMENTAL PERIOD IS DIFFERENT IN THE TWO GENERATIONS EXAMINED. THE OBTAINED RESULTS IMPROVE OUR UNDERSTANDING OF CRUSTACEAN EPIGENETICS AND THE TOOLS DEVELOPED MAY PROMOTE USE OF EPIGENETIC MARKERS IN HAZARD ASSESSMENT OF ENVIRONMENTAL STRESSORS. 2019 4 3489 21 IDENTIFICATION OF EPIGENETIC INTERACTIONS BETWEEN MICRORNA-30C-5P AND DNA METHYLTRANSFERASES IN NEUROPATHIC PAIN. NEUROPATHIC PAIN IS A PREVALENT AND SEVERE CHRONIC SYNDROME, OFTEN REFRACTORY TO TREATMENT, WHOSE DEVELOPMENT AND MAINTENANCE MAY INVOLVE EPIGENETIC MECHANISMS. WE PREVIOUSLY DEMONSTRATED A CAUSAL RELATIONSHIP BETWEEN MIR-30C-5P UPREGULATION IN NOCICEPTION-RELATED NEURAL STRUCTURES AND NEUROPATHIC PAIN IN RATS SUBJECTED TO SCIATIC NERVE INJURY. FURTHERMORE, A SHORT COURSE OF AN MIR-30C-5P INHIBITOR ADMINISTERED INTO THE CISTERNA MAGNA EXERTS LONG-LASTING ANTIALLODYNIC EFFECTS VIA A TGF-BETA1-MEDIATED MECHANISM. HEREIN, WE SHOW THAT MIR-30C-5P INHIBITION LEADS TO GLOBAL DNA HYPER-METHYLATION OF NEURONS IN THE LUMBAR DORSAL ROOT GANGLIA AND SPINAL DORSAL HORN IN RATS SUBJECTED TO SCIATIC NERVE INJURY. SPECIFICALLY, THE INHIBITION OF MIR-30-5P SIGNIFICANTLY INCREASED THE EXPRESSION OF THE NOVO DNA METHYLTRANSFERASES DNMT3A AND DNMT3B IN THOSE STRUCTURES. FURTHERMORE, WE IDENTIFIED THE MECHANISM AND FOUND THAT MIR-30C-5P TARGETS THE MRNAS OF DNMT3A AND DNMT3B. QUANTITATIVE METHYLATION ANALYSIS REVEALED THAT THE PROMOTER REGION OF THE ANTIALLODYNIC CYTOKINE TGF-BETA1 WAS HYPOMETHYLATED IN THE SPINAL DORSAL HORN OF NERVE-INJURED RATS TREATED WITH THE MIR-30C-5P INHIBITOR, WHILE THE PROMOTER OF NFYC, THE HOST GENE OF MIR-30C-5P, WAS HYPERMETHYLATED. THESE RESULTS ARE CONSISTENT WITH LONG-TERM PROTECTION AGAINST NEUROPATHIC PAIN DEVELOPMENT AFTER NERVE INJURY. ALTOGETHER, OUR RESULTS HIGHLIGHT THE KEY ROLE OF MIR-30C-5P IN THE EPIGENETIC MECHANISMS' UNDERLYING NEUROPATHIC PAIN AND PROVIDE THE BASIS FOR MIR-30C-5P AS A THERAPEUTIC TARGET. 2022 5 4923 23 PARENTAL DIURON EXPOSURE CAUSES LOWER HATCHABILITY AND ABNORMAL OVARIAN DEVELOPMENT IN OFFSPRING OF MEDAKA (ORYZIAS MELASTIGMA). DIURON IS ONE OF THE MOST WIDELY USED HERBICIDES WORLDWIDE. IT HAS BEEN WIDELY DETECTED IN VARIOUS AQUATIC ENVIRONMENTS, ESPECIALLY IN MARINE ECOSYSTEMS. ALTHOUGH DIRECT EFFECTS OF DIURON EXPOSURE ON VARIOUS ORGANISMS HAVE BEEN REPORTED, LITTLE IS KNOWN ABOUT ITS EFFECTS ON MARINE FISHES INCLUDING MULTIGENERATIONAL EFFECTS. HEREIN, THE FILIAL GENERATION (F1) OF DIURON-EXPOSED MARINE MEDAKA (ORYZIAS MELASTIGMA) (F0) WAS RAISED IN CLEAN SEAWATER FROM FERTILIZED EGGS TO ADULTHOOD AND USED AS A MARINE FISH MODEL TO STUDY THE POTENTIAL MULTIGENERATIONAL EFFECTS OF DIURON. WE FOUND THAT THE SUCCESSFUL HATCHING OF F1 LARVAE WAS SIGNIFICANTLY REDUCED AND THAT OVARIAN DEVELOPMENT IN F1 FEMALES WAS RETARDED. A SIGNIFICANT INCREASE IN THE PERCENTAGE OF PREVITELLOGENIC OOCYTES, ALONG WITH A VISUAL DECREASE IN THE PERCENTAGE OF VITELLOGENIC AND MATURE OOCYTES IN THE F1 OVARY, WERE OBSERVED. THE HORMONE LEVELS OF THE HYPOTHALAMUS-PITUITARY-GONAD-LIVER AXIS AND VITELLOGENIN-RELATED TRANSCRIPTION WERE DOWNREGULATED. IN ADDITION, THE MRNA LEVELS OF DNA METHYLTRANSFERASE IN THE BRAIN, OVARY AND LIVER OF F1 ADULT FISH EXHIBITED SIGNIFICANT UPREGULATION, SUGGESTING THAT THE PROBABLE UNDERLYING MULTIGENERATIONAL MECHANISM MIGHT BE ASSOCIATED WITH EPIGENETIC MODIFICATIONS. TAKEN TOGETHER, THESE RESULTS DEMONSTRATED THAT CHRONIC ENVIRONMENTAL DIURON EXPOSURE IN F0 MARINE MEDAKA CAN INHIBIT F1 OVARY DEVELOPMENT AND SUGGESTED THAT DIURON MAY AFFECT MARINE FISH THRIVING IN THE OCEAN. 2022 6 2698 27 EXAMINING MULTI- AND TRANSGENERATIONAL BEHAVIORAL AND MOLECULAR ALTERATIONS RESULTING FROM PARENTAL EXPOSURE TO AN ENVIRONMENTAL PCB AND PBDE MIXTURE. POLYCHLORINATED BIPHENYLS (PCBS) AND POLYBROMINATED DIPHENYL ETHERS (PBDES) ARE PERSISTENT ORGANIC POLLUTANTS EXTENSIVELY USED DURING THE 20(TH) CENTURY AND STILL PRESENT IN AQUATIC ENVIRONMENTS DESPITE THEIR BAN. EFFECTS OF EXPOSURE TO THESE COMPOUNDS OVER GENERATIONS ARE POORLY DOCUMENTED. THEREFORE, OUR AIMS WERE TO CHARACTERIZE BEHAVIORAL RESPONSES AND UNDERLYING MOLECULAR MECHANISMS IN ZEBRAFISH EXPOSED TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PCBS AND PBDES AS WELL AS IN FOUR UNEXPOSED OFFSPRING GENERATIONS. ZEBRAFISH (F0) WERE CHRONICALLY EXPOSED FROM THE FIRST MEAL ONWARD TO A DIET SPIKED WITH A MIXTURE CONTAINING 22 PCB AND 7 PBDE CONGENERS IN PROPORTIONS AND CONCENTRATIONS REFLECTING ENVIRONMENTAL SITUATIONS (SIGMAPCBS = 1991 AND SIGMAPBDES = 411 NG/G). FOUR OFFSPRING GENERATIONS (F1 TO F4) WERE OBTAINED FROM THIS F0 AND WERE NOT FURTHER EXPOSED. BEHAVIOR WAS ASSESSED AT BOTH LARVAL AND ADULT STAGES. MECHANISMS RELATED TO BEHAVIORAL DEFECTS (HABENULA MATURATION AND C-FOS TRANSCRIPTION) AND METHYLATION (DNMTS TRANSCRIPTION) WERE MONITORED IN LARVAE. EXPOSED ADULT F0 AS WELL AS F1 AND F3 ADULTS DISPLAYED NO BEHAVIORAL CHANGE WHILE F2 EXPRESSED ANXIETY-LIKE BEHAVIOR. LARVAL BEHAVIOR WAS ALSO DISRUPTED, I.E. HYPERACTIVE AFTER LIGHT TO DARK TRANSITION IN F1 OR HYPOACTIVE IN F2, F3 AND F4. BEHAVIORAL DISRUPTIONS MAY BE RELATED TO DEFECT IN HABENULA MATURATION (OBSERVED IN F1) AND CHANGE IN C-FOS TRANSCRIPTION (OBSERVED IN F1 AND F2). TRANSCRIPTION OF THE GENE ENCODING DNA METHYLTRANSFERASE (DNMT3BA) WAS ALSO MODIFIED IN ALL GENERATIONS. OUR RESULTS LEAD US TO HYPOTHESIZE THAT CHRONIC DIETARY EXPOSURE TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PCB AND PBDE TRIGGERS MULTIGENERATIONAL AND TRANSGENERATIONAL MOLECULAR AND BEHAVIORAL DISRUPTIONS IN A VERTEBRATE MODEL. 2019 7 3810 21 INTRATHECAL 5-AZACYTIDINE INHIBITS GLOBAL DNA METHYLATION AND METHYL- CPG-BINDING PROTEIN 2 EXPRESSION AND ALLEVIATES NEUROPATHIC PAIN IN RATS FOLLOWING CHRONIC CONSTRICTION INJURY. THE PATHOGENESIS OF NEUROPATHIC PAIN REMAINS LARGELY UNKNOWN. EPIGENETIC MECHANISMS MAY PLAY A MAJOR ROLE IN REGULATING EXPRESSION OF PRO- OR ANTINOCICEPTIVE GENES. DNA METHYLATION IS A MAJOR EPIGENETIC MECHANISM IN VERTEBRATES, AND METHYL- CPG-BINDING PROTEIN 2 (MECP2) IS DIRECTLY INVOLVED IN METHYLATION-MEDIATED GENE SILENCING. TO DETERMINE HOW CHANGES IN GLOBAL DNA METHYLATION AND MECP2 EXPRESSION OCCUR FOLLOWING CHRONIC CONSTRICTION INJURY (CCI) AND HOW REPRESSION OF DNA METHYLATION AFFECTS THESE CHANGES AND ATTENUATES NEUROPATHIC PAIN, WE USED INTRATHECAL 5-AZACYTIDINE, A DNA METHYLTRANSFERASE INHIBITOR, IN CCI RATS. RATS RECEIVED 0.9% SALINE OR 5-AZACYTIDINE (10MUMOL.D(-1)) VIA SPINAL INJECTION ONCE DAILY FROM DAY 3 TO DAY 14 AFTER CCI SURGERY. GLOBAL DNA METHYLATION AND MECP2 EXPRESSION INCREASED IN THE SPINAL CORD IN CCI RATS ON DAY 14 AFTER CCI SURGERY. MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA INDUCED BY CCI WERE ATTENUATED BY INTRATHECAL 5-AZACYTIDINE FROM DAY 5 TO DAY 14 AFTER CCI SURGERY. THE INCREASES IN GLOBAL DNA METHYLATION AND MECP2 EXPRESSION IN THE SPINAL CORD IN CCI RATS WERE ALSO SIGNIFICANTLY INHIBITED BY INTRATHECAL 5-AZACYTIDINE. THESE RESULTS DEMONSTRATE THAT INCREASED GLOBAL DNA METHYLATION AND MECP2 EXPRESSION IN THE SPINAL CORD AFTER NERVE DAMAGE MAY PLAY AN IMPORTANT ROLE IN NEUROPATHIC PAIN. 5-AZACYTIDINE SHOWS POTENTIAL FOR TREATING NEUROPATHIC PAIN. 2011 8 6918 19 [WNT3A SIGNALING PATHWAY PLAYS A ROLE IN NEUROPATHIC PAIN THROUGH EPIGENETIC MODIFICATION OF JMJD6]. TO EXPLORE WHETHER WNT3A EXERTS A ROLE IN NEUROPATHIC PAIN THROUGH JUMONJI C DOMAIN 6 (JMJD6)-ASSOCIATED EPIGENETIC MODIFICATION. METHODS: SD RATS WERE DIVIDED INTO 4 GROUPS: A SHAM GROUP, A CHRONIC CONSTRICTION INJURY (CCI) GROUP, A CCI+NEGATIVE LENTIVIRAL EXPRESSION VECTOR (LV-NC) GROUP AND A CCI+LENTIVIRAL OVEREXPRESSION VECTOR (LV-JMJD6) GROUP. THE SCIATIC NERVE CCI MODEL OF SD RAT AND JMJD6 LENTIVIRAL EXPRESSION VECTOR WERE CONSTRUCTED. ON THE THIRD DAY AFTER CCI, THE INTRATHECAL CATHETER WAS PREPARED, AND 20 MUL OF NORMAL SALINE AND LENTIVIRUS-CONTAINING REAGENT (VIRUS TITER 1X108 TU/ML) WERE ADMINISTERED. THE RATS' PAW WITHDRAWAL MECHANICAL THRESHOLD (PWMT) AND PAW WITHDRAWAL THERMAL LATENCY (PWTL) WERE MONITORED, AND WESTERN BLOTTING WAS USED TO DETECT THE EXPRESSION OF WNT3A AND NR2B PROTEIN IN THE SPINAL CORD. CO-IMMUNOPRECIPITATION WAS APPLIED TO DETECT THE INTERACTION BETWEEN JMJD6 AND WNT3A. RESULTS: COMPARED WITH THE SHAM GROUP, THE PWMT OF THE RATS IN EACH GROUP AFTER CCI WAS SIGNIFICANTLY DECREASED AND THE PWTL WAS SIGNIFICANTLY SHORTENED (P<0.05). COMPARED WITH THE CCI GROUP AND THE CCI+LV-NC GROUP, PWMT IN THE CCI+LV-JMJD6 GROUP WAS INCREASED SIGNIFICANTLY ON THE 10TH DAY AND THE 14TH DAY AFTER CCI, AND THE PWTL WAS SIGNIFICANTLY PROLONGED ON THE 14TH DAY AFTER CCI (P<0.05). ON THE 14TH DAY AFTER CCI, THE EXPRESSION LEVELS OF WNT3A AND NR2B IN THE CCI GROUP AND THE CCI+LV-NC GROUP WERE SIGNIFICANTLY HIGHER THAN THOSE IN THE SHAM GROUP. AFTER INTRATHECAL INJECTION OF LENTIVIRAL VECTOR, WNT3A AND NR2B PROTEIN EXPRESSION LEVELS IN THE CCI+LV-JMJD6 GROUP WERE LOWER COMPARED WITH THE CCI+LV-NC GROUP (P<0.05). THE RESULTS OF CO-IMMUNOPRECIPITATION SHOWED NO DIRECT INTERACTION BETWEEN WNT3A AND JMJD6. CONCLUSION: WNT3A IS INVOLVED IN MEDIATING NEUROPATHIC PAIN, AND ITS EFFECT MAY BE RELATED TO THE EPIGENETIC MODIFICATION OF JMJD6, WHICH IS LIKELY REGULATED THROUGH INDIRECT INTERACTION. 2019 9 5976 13 TET1-DEPENDENT EPIGENETIC MODIFICATION OF BDNF EXPRESSION IN DORSAL HORN NEURONS MEDIATES NEUROPATHIC PAIN IN RATS. TEN-ELEVEN TRANSLOCATION METHYLCYTOSINE DIOXYGENASE 1 (TET1) MEDIATES THE CONVERSION OF 5-METHYLCYTOSINE (5 MC) TO 5-HYDROXYMETHYLCYTOSINE (5 HMC), HENCE PROMOTING DNA DEMETHYLATION. ALTHOUGH RECENT STUDIES HAVE LINKED THE DNA DEMETHYLATION OF SPECIFIC GENES TO PAIN HYPERSENSITIVITY, THE ROLE OF SPINAL TET1-DEPENDENT DNA DEMETHYLATION IN NOCICEPTION HYPERSENSITIVITY DEVELOPMENT REMAINS ELUSIVE. HERE, WE REPORT CORRELATED WITH BEHAVIORAL ALLODYNIA, SPINAL NERVE LIGATION (SNL) UPREGULATED TET1 EXPRESSION IN DORSAL HORN NEURONS THAT HYDROXYLATE 5 MC TO 5 HMC AT CPG DINUCLEOTIDES IN THE BDNF PROMOTER TO PROMOTE SPINAL BDNF EXPRESSION AT DAY 7 AFTER OPERATION. FOCAL KNOCKDOWN OF SPINAL TET1 EXPRESSION DECREASED TET1 BINDING AND 5 HMC ENRICHMENT, FURTHER INCREASED 5 MC ENRICHMENT AT CPG SITES IN THE BDNF PROMOTER AND DECREASED SPINAL BDNF EXPRESSION ACCOMPANIED BY THE ALLEVIATION OF THE DEVELOPED ALLODYNIA. MOREOVER, AT DAY 7 AFTER OPERATION, SNL-ENHANCED TET1 EXPRESSION ALSO INHIBITED THE BINDING OF DNA METHYLTRANSFERASES (DNMTS, I.E., DNMT1, DNMT3A, AND DNMT3B) TO THE BDNF PROMOTER, A REQUIREMENT FOR TRANSCRIPTIONAL SILENCING BY CATALYSING 5-CYTOSINE (5C) TO 5 MC. TOGETHER, THESE DATA SUGGEST AT CPG SITES OF THE BDNF PROMOTER, SNL-ENHANCED TET1 EXPRESSION PROMOTES DNA DEMETHYLATION BOTH BY CONVERTING 5 MC TO 5 HMC AND INHIBITING DNMT BINDING TO REGULATE SPINAL BDNF EXPRESSION, HENCE CONTRIBUTING TO BEHAVIORAL ALLODYNIA DEVELOPMENT. 2016 10 6612 22 ULTRA-LOW-DOSE NALOXONE ENHANCES THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN PTX-TREATED RATS: REGULATION ON GLOBAL HISTONE METHYLATION. OBJECTIVE: EPIGENETIC REPROGRAMMING MAY HAVE A POSSIBLE ROLE IN NEUROPATHIC PAIN DEVELOPMENT; THE PRESENT STUDY EXAMINED THE GLOBAL PATTERNS OF LYSINE HISTONE MODIFICATION. IN THIS SERIAL STUDY WE ANALYZED THE LEVELS OF HISTONE 3 LYSINE 4 MONOMETHYLATION, HISTONE 3 LYSINE 4 DIMETHYLATION, AND HISTONE 3 LYSINE 9 TRIMETHYLATION IN PERTUSSIS TOXIN (PTX)-INDUCED THERMAL HYPERALGESIC RAT SPINAL CORDS. METHODS: MALE WISTAR RATS IMPLANTED WITH AN INTRATHECAL CATHETER RECEIVED A SINGLE INTRATHECAL PTX (1 MUG IN 5 MUL SALINE) INJECTION. FOUR DAYS LATER, THEY WERE RANDOMLY ASSIGNED TO RECEIVE EITHER A SINGLE INJECTION OF SALINE, OR ULTRA-LOW-DOSE NALOXONE (15 NG IN 5 MUL SALINE), FOLLOWED BY MORPHINE (10 MUG IN 5 MUL SALINE) INJECTION 30 MINUTES LATER. RESULTS: THE RESULTS SHOWED THAT PTX INJECTION INDUCED THERMAL HYPERALGESIA AND SIGNIFICANT INCREASE OF GLOBAL HISTONE METHYLATION IN THE SPINAL CORDS. INTRATHECAL MORPHINE ALONE DID NOT AFFECT THE THERMAL HYPERALGESIA AND GLOBAL HISTONE METHYLATION. IN CONTRAST, INTRATHECAL ADMINISTRATION OF ULTRA-LOW-DOSE NALOXONE PLUS MORPHINE SIGNIFICANTLY ATTENUATED THE PTX-INDUCED THERMAL HYPERALGESIA AND DOWN-REGULATED THE GLOBAL HISTONE METHYLATION. CONCLUSION: THE RESULTS SUGGEST THAT ULTRA-LOW-DOSE NALOXONE MIGHT BE CLINICAL VALUABLE FOR NEUROPATHIC PAIN MANAGEMENT VIA REGULATING GLOBAL HISTONE MODIFICATION. 2012 11 2667 20 ESTROGEN AND SEROTONIN ENHANCE STRESS-INDUCED VISCERAL HYPERSENSITIVITY IN FEMALE RATS BY UP-REGULATING BRAIN-DERIVED NEUROTROPHIC FACTOR IN SPINAL CORD. BACKGROUND: WE PREVIOUSLY REPORTED THAT FEMALE OFFSPRING OF DAMS SUBJECTED TO CHRONIC PRENATAL STRESS (CPS) DEVELOP ENHANCED VISCERAL HYPERSENSITIVITY (VHS) FOLLOWING EXPOSURE TO CHRONIC STRESS IN ADULT LIFE THAT IS MEDIATED BY UP-REGULATION OF SPINAL CORD BDNF. THE AIMS OF THIS STUDY WERE TO EXAMINE THE ROLES OF ESTROGEN RECEPTOR ALPHA (ERALPHA) AND AN INCREASE IN SPINAL SEROTONIN SIGNALING IN PROMOTING THIS ENHANCED VHS IN FEMALE RATS AND UP-REGULATION OF SPINAL CORD BDNF TRANSCRIPTION. METHODS: PREGNANT DAMS WERE EXPOSED TO CHRONIC STRESS FROM E11 UNTIL DELIVERY. AT 8 WEEKS, A CHRONIC ADULT STRESS (CAS) PROTOCOL WAS APPLIED FOR NINE DAYS. KEY RESULTS: OVARIECTOMY BEFORE CAS OR TREATMENT WITH LETROZOLE BEFORE AND DURING CAS SIGNIFICANTLY PREVENTED THE DEVELOPMENT OF ENHANCED VHS IN FEMALE CPS+CAS RATS. INTRATHECAL APPLICATION OF ERALPHA SIRNA SIGNIFICANTLY REDUCED VHS, DECREASED LUMBAR-SACRAL SPINAL CORD EXPRESSION OF BOTH ERALPHA AND BDNF, AND REVERSED PRO-TRANSCRIPTIONAL EPIGENETIC MODIFICATIONS AT BDNF PROMOTER LX. CEREBROSPINAL FLUID SEROTONIN LEVELS AND 5HT3A RECEPTOR EXPRESSION IN THE LS SPINAL CORD WERE BOTH SIGNIFICANTLY INCREASED IN FEMALE CPS+CAS RATS. DURING CAS, INTRATHECAL INFUSION OF ALOSETRON SIGNIFICANTLY DECREASED VHS, REDUCED BDNF AND ERALPHA EXPRESSION IN THE LS SPINAL CORD, AND ATTENUATED RNA POL II AND ERALPHA BINDING TO THE BNDF CORE PROMOTER IX. CONCLUSIONS & INFERENCES: SEROTONIN-MEDIATED ACTIVATION OF 5HT3A RECEPTORS IN THE SPINAL CORD DRIVES THE DEVELOPMENT OF ENHANCED FEMALE-SPECIFIC VHS IN OUR TWO HIT CPS+CAS THROUGH UP-REGULATION OF SPINAL CORD ERALPHA. 2021 12 3809 26 INTRAPERITONEAL 5-AZACYTIDINE ALLEVIATES NERVE INJURY-INDUCED PAIN IN RATS BY MODULATING DNA METHYLATION. TO INVESTIGATE THE ROLE OF DNA METHYLATION IN MODULATING CHRONIC NEUROPATHIC PAIN (NPP), IDENTIFY POSSIBLE TARGET GENES OF DNA METHYLATION INVOLVED IN THIS PROCESS, AND PRELIMINARILY CONFIRM THE MEDICINAL VALUE OF THE DNA METHYLTRANSFERASES (DNMTS) INHIBITOR 5-AZACYTIDINE (5-AZA) IN NPP BY TARGETING GENE METHYLATION. TWO RAT NPP MODELS, CHRONIC CONSTRICTION INJURY (CCI) AND SPINAL NERVE LIGATION (SNL), WERE USED. THE DNA METHYLATION PROFILES IN THE LUMBAR SPINAL CORD WERE ASSAYED USING AN ARRAYSTAR RAT REFSEQ PROMOTER ARRAY. THE UNDERLYING GENES WITH DIFFERENTIAL METHYLATION WERE THEN IDENTIFIED AND SUBMITTED TO GENE ONTOLOGY AND PATHWAY ANALYSIS. METHYL-DNA IMMUNOPRECIPITATION QUANTITATIVE PCR (MEDIP-QPCR) AND QUANTITATIVE REVERSE TRANSCRIPTION-PCR (RT-QPCR) WERE USED TO CONFIRM GENE METHYLATION AND EXPRESSION. THE PROTECTIVE FUNCTION OF 5-AZA IN NPP AND GENE EXPRESSION WERE EVALUATED VIA BEHAVIORAL ASSAYS AND RT-QPCR, RESPECTIVELY. ANALYSIS OF THE DNA METHYLATION PATTERNS IN THE LUMBAR SPINAL CORD INDICATED THAT 1205 DIFFERENTIALLY METHYLATED FRAGMENTS IN CCI RATS WERE LOCATED WITHIN DNA PROMOTER REGIONS, INCLUDING 638 HYPERMETHYLATED FRAGMENTS AND 567 HYPOMETHYLATED FRAGMENTS. THE METHYLATION LEVELS OF GRM4, HTR4, ADRB2, KCNF1, GAD2, AND PPARG, WHICH ARE ASSOCIATED WITH LONG-TERM POTENTIATION (LTP) AND GLUTAMATERGIC SYNAPSE PATHWAYS, WERE INCREASED WITH A CORRESPONDING DECREASE IN THEIR MRNA EXPRESSION, IN THE SPINAL CORDS OF CCI RATS. MOREOVER, WE FOUND THAT THE INTRAPERITONEAL INJECTION OF 5-AZA (4 MG/KG) ATTENUATED CCI- OR SNL-INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA. FINALLY, THE MRNA EXPRESSION OF HYPERMETHYLATED GENES SUCH AS GRM4, HTR4, ADRB2, KCNF1, AND GAD2 WAS REVERSED AFTER 5-AZA TREATMENT. CCI INDUCED WIDESPREAD METHYLATION CHANGES IN THE DNA PROMOTER REGIONS IN THE LUMBAR SPINAL CORD. INTRAPERITONEAL 5-AZA ALLEVIATED HYPERALGESIA IN CCI AND SNL RATS, AN EFFECT ACCOMPANIED BY THE REVERSED EXPRESSION OF HYPERMETHYLATED GENES. THUS, DNA METHYLATION INHIBITION REPRESENTS A PROMISING EPIGENETIC STRATEGY FOR PROTECTION AGAINST CHRONIC NPP FOLLOWING NERVE INJURY. OUR STUDY LAYS A THEORETICAL FOUNDATION FOR 5-AZA TO BECOME A CLINICAL TARGETED DRUG. 2023 13 3109 30 GENOTOXIC AND EPIGENETIC EFFECTS OF DIURON IN THE PACIFIC OYSTER: IN VITRO EVIDENCE OF INTERACTION BETWEEN DNA DAMAGE AND DNA METHYLATION. RECENTLY, RESEARCH HAS CONTRIBUTED TO BETTER KNOWLEDGE ON THE OCCURRENCE OF PESTICIDES IN COASTAL WATER BY IDENTIFYING FREQUENTLY DETECTED SUBSTANCES, THEIR CONCENTRATION RANGE AND THEIR ACUTE AND CHRONIC TOXICITY FOR ORGANISMS. PESTICIDE POLLUTION IS OF PARTICULAR CONCERN IN FRANCE DUE TO IMPORTANT AGRICULTURAL ACTIVITIES AND PRESENCE OF SEVERAL EXOREIC CATCHMENT AREAS THAT VEHICLE PESTICIDES UP TO COASTAL WATERS, IMPACTING NON-TARGET MARINE SPECIES. SEVERAL ECOTOXICOLOGY QUESTIONS REMAIN TO BE ADDRESSED CONCERNING THE LONG-TERM EFFECTS OF CHRONIC PESTICIDE EXPOSURE AND THE MECHANISMS INVOLVED IN ADAPTATION TO CHEMICAL STRESS. IN THE PRESENT STUDY, WE BROUGHT NEW INSIGHTS ON THE GENETIC AND EPIGENETIC EFFECTS OF THE HERBICIDE DIURON IN OYSTER GENITORS. DURING GAMETOGENESIS, WE EXPOSED CRASSOSTREA GIGAS TO ENVIRONMENTALLY REALISTIC HERBICIDE CONCENTRATIONS (0.2-0.3 MUG L(-1) DURING TWO 7-DAY PERIODS AT HALF-COURSE AND END OF GAMETOGENESIS). DIURON EXPOSURE WAS SHOWN TO DECREASE GLOBAL DNA METHYLATION AND TOTAL METHYLTRANSFERASE ACTIVITY IN WHOLE OYSTER TISSUE; THIS IS CONSISTENT WITH THE PREVIOUS OBSERVATION OF A SIGNIFICANT DECREASE IN DNMT1 GENE EXPRESSION. DIURON EFFECT SEEMED TO BE TISSUE-SPECIFIC; HYPERMETHYLATION WAS DETECTED IN THE DIGESTIVE GLAND, WHEREAS DIURON EXPOSURE HAD NO EFFECT ON GILL AND GONAD TISSUE. THE GENOTOXICITY OF DIURON WAS CONFIRMED BY THE DETECTION OF ONE ADDUCT IN GONAD DNA. BY USING IN VITRO APPROACHES AND HUMAN DNMT1 (DNMT1 HAS NOT BEEN PURIFIED YET IN BIVALVES), THE PRESENCE OF DNA LESIONS (ADDUCT, 8-OXODGUO) WAS SHOWN TO INTERFERE WITH DNMT1 ACTIVITY, INDICATING A COMPLEX INTERACTION BETWEEN DNA DAMAGE AND DNA METHYLATION. BASED ON OUR RESULTS, WE PROPOSE MECHANISMS TO EXPLAIN THE EFFECT OF DIURON EXPOSURE ON DNA METHYLATION, A WIDESPREAD EPIGENETIC MARK. 2021 14 1816 25 EFFECTS OF CHRONIC EXPOSURE TO BENZOPHENONE AND DICLOFENAC ON DNA METHYLATION LEVELS AND REPRODUCTIVE SUCCESS IN A MARINE COPEPOD. THE UV-FILTER BENZOPHENONE AND THE ANTI-INFLAMMATORY DICLOFENAC ARE COMMONLY DETECTED IN THE ENVIRONMENT. THE AIM OF THIS STUDY WAS TO ASSESS THE MULTIGENERATIONAL EFFECTS OF CHRONIC EXPOSURE TO LOW CONCENTRATIONS OF THESE CHEMICALS ON TOXICITY AND DNA METHYLATION LEVELS IN THE COPEPOD GLADIOFERENS PECTINATUS. ACUTE TOXICITY TESTS WERE CONDUCTED TO DETERMINE THE SENSITIVITY OF G. PECTINATUS TO THE CHEMICALS. ALL CHEMICALS IMPACTED BREEDING, HATCHING AND EGG VIABILITY. DICLOFENAC (1 MG.L(-1)) REDUCED THE NUMBER OF EGGS PER GRAVID FEMALE. BENZOPHENONE (0.5 MG.L(-1)) DECREASED EGG HATCHING SUCCESS. EXPOSURE TO THE REFERENCE TOXICANT COPPER (0.02 MG.L(-1)) LED TO UNSUCCESSFUL HATCHING. EFFECTS ON DNA METHYLATION WAS ESTIMATED BY THE PERCENTAGE OF 5- METHYLCYTOSINE. THE TREATMENTS RESULTED IN STRONG DIFFERENCES IN DNA METHYLATION WITH INCREASED METHYLATION IN THE EXPOSED ANIMALS. THE TWO CHEMICALS IMPACTED BOTH EGG VIABILITY AND THE INDUCTION OF DIFFERENTIAL DNA METHYLATION, SUGGESTING POTENTIAL INTRA- AND TRANS-GENERATIONAL EVOLUTIONARY EFFECTS. 2018 15 5354 22 RE1-SILENCING TRANSCRIPTION FACTOR CONTROLS THE ACUTE-TO-CHRONIC NEUROPATHIC PAIN TRANSITION AND CHRM2 RECEPTOR GENE EXPRESSION IN PRIMARY SENSORY NEURONS. NEUROPATHIC PAIN IS ASSOCIATED WITH PERSISTENT CHANGES IN GENE EXPRESSION IN PRIMARY SENSORY NEURONS, BUT THE UNDERLYING EPIGENETIC MECHANISMS THAT CAUSE THESE CHANGES REMAIN UNCLEAR. THE MUSCARINIC CHOLINERGIC RECEPTORS (MACHRS), PARTICULARLY THE M2 SUBTYPE (ENCODED BY THE CHOLINERGIC RECEPTOR MUSCARINIC 2 (CHRM2) GENE), ARE CRITICALLY INVOLVED IN THE REGULATION OF SPINAL NOCICEPTIVE TRANSMISSION. HOWEVER, LITTLE IS KNOWN ABOUT HOW CHRM2 EXPRESSION IS TRANSCRIPTIONALLY REGULATED. HERE WE SHOW THAT NERVE INJURY PERSISTENTLY INCREASED THE EXPRESSION OF RE1-SILENCING TRANSCRIPTION FACTOR (REST, ALSO KNOWN AS NEURON-RESTRICTIVE SILENCING FACTOR [NRSF]), A GENE-SILENCING TRANSCRIPTION FACTOR, IN THE DORSAL ROOT GANGLION (DRG). REMARKABLY, NERVE INJURY-INDUCED CHRONIC BUT NOT ACUTE PAIN HYPERSENSITIVITY WAS ATTENUATED IN MICE WITH REST KNOCKOUT IN DRG NEURONS. ALSO, SIRNA-MEDIATED REST KNOCKDOWN REVERSED NERVE INJURY-INDUCED CHRONIC PAIN HYPERSENSITIVITY IN RATS. NERVE INJURY PERSISTENTLY REDUCED CHRM2 EXPRESSION IN THE DRG AND DIMINISHED THE ANALGESIC EFFECT OF MUSCARINE. THE RE1 BINDING SITE ON THE CHRM2 PROMOTER IS REQUIRED FOR REST-MEDIATED CHRM2 REPRESSION, AND NERVE INJURY INCREASED THE ENRICHMENT OF REST IN THE CHRM2 PROMOTER IN THE DRG. FURTHERMORE, REST KNOCKDOWN OR GENETIC ABLATION IN DRG NEURONS NORMALIZED CHRM2 EXPRESSION AND AUGMENTED MUSCARINE'S ANALGESIC EFFECT ON NEUROPATHIC PAIN AND FULLY REVERSED THE NERVE INJURY-INDUCED REDUCTION IN THE INHIBITORY EFFECT OF MUSCARINE ON GLUTAMATERGIC INPUT TO SPINAL DORSAL HORN NEURONS. OUR FINDINGS INDICATE THAT NERVE INJURY-INDUCED REST UP-REGULATION IN DRG NEURONS PLAYS AN IMPORTANT ROLE IN THE ACUTE-TO-CHRONIC PAIN TRANSITION AND IS ESSENTIAL FOR THE TRANSCRIPTIONAL REPRESSION OF CHRM2 IN NEUROPATHIC PAIN. 2018 16 4579 18 N(6)-METHYLADENOSINE METHYLASE METTL3 CONTRIBUTES TO NEUROPATHIC PAIN BY EPIGENETIC SILENCING OF MU OPIOID RECEPTOR. WE AIMED AT EXPLORING THE ROLE AND MECHANISM OF METTL3-MEDIATED M(6)A MODIFICATION IN NEUROPATHIC PAIN. MALE SPRAGUE-DAWLEY RATS WERE RANDOMLY DIVIDED INTO FOUR GROUPS: SHAM OPERATION GROUP (SHAM GROUP), CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE MODEL GROUP (NPP GROUP), INTRATHECAL INJECTION OF VIRUS DOWN-REGULATED METTL3 + CCI MODEL GROUP (M3 + NPP GROUP) AND INTRATHECAL INJECTION OF NEGATIVE CONTROL VIRUS + CCI MODEL GROUP (SCR + NPP GROUP). THE M3 + NPP GROUP AND THE SCR + NPP GROUP WERE INTRATHECALLY INJECTED WITH VIRUS NINETEEN DAYS BEFORE OPERATION. THE PAW WITHDRAWAL MECHANICAL THRESHOLDS AND PAW WITHDRAWAL LATENCY WERE RESPECTIVELY RECORDED ONE DAY BEFORE OPERATION, THREE DAYS, FIVE DAYS AND SEVEN DAYS AFTER OPERATION. THE RATS WERE SACRIFICED ON THE SEVENTH DAY AFTER OPERATION, AND THEIR SPINAL CORD TISSUES WERE TAKEN. THE FROZEN SECTIONS OF RATS WERE PERFORMED TO OBSERVE THE EXPRESSION OF GREEN FLUORESCENT PROTEIN OF THE VIRUS. THE METHYLATION LEVEL OF RNA, THE PROTEIN EXPRESSION OF M(6)A-RELATED ENZYME (METTL3) AND MU OPIOID RECEPTOR (MOR) IN SPINAL CORD TISSUES OF THE FOUR GROUPS WERE MEASURED. DOWNREGULATION OF METTL3 HAD NO EFFECT ON THE OVERALL METHYLATION LEVEL OF THE SPINAL CORD, BUT IT COULD REGULATE THE METHYLATION LEVEL OF THE OPRM1 GENE RNA ENCODING MOR, PARTIALLY RESTORE THE EXPRESSION OF MOR, AND RELIEVE PAIN IN RATS. IN THE PROCESS OF NPP, METTL3 MAY INHIBIT THE EXPRESSION OF MOR BY REGULATING THE METHYLATION LEVEL OF OPRM1 GENE RNA ENCODING MOR, AND ULTIMATELY PROMOTE THE OCCURRENCE AND DEVELOPMENT OF NPP. 2023 17 1706 26 DYNORPHIN/KOP AND NOCICEPTIN/NOP GENE EXPRESSION AND EPIGENETIC CHANGES BY COCAINE IN RAT STRIATUM AND NUCLEUS ACCUMBENS. COCAINE INDUCES NEUROCHEMICAL CHANGES OF ENDOGENOUS PRODYNORPHIN-KAPPA OPIOID RECEPTOR (PDYN-KOP) AND PRONOCICEPTIN/ORPHANINFQ-NOCICEPTIN RECEPTOR (PN/OFQ-NOP) SYSTEMS. BOTH SYSTEMS PLAY AN IMPORTANT ROLE IN REWARDING MECHANISMS AND ADDICTIVE STIMULUS PROCESSING BY MODULATING DRUG-INDUCED DOPAMINERGIC ACTIVATION IN THE MESOCORTICO-LIMBIC BRAIN AREAS. THEY ARE ALSO INVOLVED IN REGULATING STRESS MECHANISMS RELATED TO ADDICTION. THE AIM OF THIS STUDY WAS TO INVESTIGATE POSSIBLE CHANGES OF GENE EXPRESSION OF THE DYNORPHINERGIC AND NOCICEPTINERGIC SYSTEM COMPONENTS IN THE NUCLEUS ACCUMBENS (NA) AND IN MEDIAL AND LATERAL CAUDATE PUTAMEN (MCPU AND LCPU, RESPECTIVELY) OF RATS, FOLLOWING CHRONIC SUBCUTANEOUS INFUSION OF COCAINE. IN ADDITION, THE EPIGENETIC HISTONE MODIFICATIONS H3K4ME3 AND H3K27ME3 (AN ACTIVATING AND A REPRESSIVE MARKER, RESPECTIVELY) AT THE PROMOTER LEVEL OF THE PDYN, KOP, PN/OFQ AND NOP GENES WERE INVESTIGATED. RESULTS SHOWED THAT COCAINE INDUCED PDYN GENE EXPRESSION UP-REGULATION IN THE NA AND LCPU, AND ITS DOWN-REGULATION IN THE MCPU, WHEREAS KOP MRNA LEVELS WERE UNCHANGED. MOREOVER, COCAINE EXPOSURE DECREASED PN/OFQ GENE EXPRESSION IN THE NA AND LCPU, WHILE NOP MRNA LEVELS APPEARED SIGNIFICANTLY INCREASED IN THE NA AND DECREASED IN THE LCPU. SPECIFIC CHANGES OF THE H3K4ME3 AND H3K27ME3 LEVELS WERE FOUND AT PDYN, PN/OFQ, AND NOP GENE PROMOTER, CONSISTENT WITH THE OBSERVED GENE EXPRESSION ALTERATIONS. THE PRESENT FINDINGS CONTRIBUTE TO BETTER DEFINE THE ROLE OF ENDOGENOUS PDYN-KOP AND PN/OFQ-NOP SYSTEMS IN NEUROPLASTICITY MECHANISMS FOLLOWING CHRONIC COCAINE TREATMENT. THE EPIGENETIC HISTONE MODIFICATIONS UNDERLYING THE GENE EXPRESSION CHANGES LIKELY MEDIATE THE EFFECTS OF COCAINE ON TRANSCRIPTIONAL REGULATION OF SPECIFIC GENE PROMOTERS THAT RESULT IN LONG-LASTING DRUG-INDUCED PLASTICITY. 2014 18 4919 26 PANNEXIN-1 UP-REGULATION IN THE DORSAL ROOT GANGLION CONTRIBUTES TO NEUROPATHIC PAIN DEVELOPMENT. PANNEXIN-1 (PANX1) IS A LARGE-PORE MEMBRANE CHANNEL INVOLVED IN THE RELEASE OF ATP AND OTHER SIGNALING MEDIATORS. LITTLE IS KNOWN ABOUT THE EXPRESSION AND FUNCTIONAL ROLE OF PANX1 IN THE DORSAL ROOT GANGLION (DRG) IN THE DEVELOPMENT OF CHRONIC NEUROPATHIC PAIN. IN THIS STUDY, WE DETERMINED THE EPIGENETIC MECHANISM INVOLVED IN INCREASED PANX1 EXPRESSION IN THE DRG AFTER NERVE INJURY. SPINAL NERVE LIGATION IN RATS SIGNIFICANTLY INCREASED THE MRNA AND PROTEIN LEVELS OF PANX1 IN THE DRG BUT NOT IN THE SPINAL CORD. IMMUNOCYTOCHEMICAL LABELING SHOWED THAT PANX1 WAS PRIMARILY EXPRESSED IN A SUBSET OF MEDIUM AND LARGE DRG NEURONS IN CONTROL RATS AND THAT NERVE INJURY MARKEDLY INCREASED THE NUMBER OF PANX1-IMMUNOREACTIVE DRG NEURONS. NERVE INJURY SIGNIFICANTLY INCREASED THE ENRICHMENT OF TWO ACTIVATING HISTONE MARKS (H3K4ME2 AND H3K9AC) AND DECREASED THE OCCUPANCY OF TWO REPRESSIVE HISTONE MARKS (H3K9ME2 AND H3K27ME3) AROUND THE PROMOTER REGION OF PANX1 IN THE DRG. HOWEVER, NERVE INJURY HAD NO EFFECT ON THE DNA METHYLATION LEVEL AROUND THE PANX1 PROMOTER IN THE DRG. FURTHERMORE, INTRATHECAL INJECTION OF THE PANX1 BLOCKERS OR PANX1-SPECIFIC SIRNA SIGNIFICANTLY REDUCED PAIN HYPERSENSITIVITY INDUCED BY NERVE INJURY. IN ADDITION, SIRNA KNOCKDOWN OF PANX1 EXPRESSION IN A DRG CELL LINE SIGNIFICANTLY REDUCED CASPASE-1 RELEASE INDUCED BY NEURONAL DEPOLARIZATION. OUR FINDINGS SUGGEST THAT NERVE INJURY INCREASES PANX1 EXPRESSION LEVELS IN THE DRG THROUGH ALTERED HISTONE MODIFICATIONS. PANX1 UP-REGULATION CONTRIBUTES TO THE DEVELOPMENT OF NEUROPATHIC PAIN AND STIMULATION OF INFLAMMASOME SIGNALING. 2015 19 3368 21 HISTONE METHYLTRANSFERASE G9A DIMINISHES EXPRESSION OF CANNABINOID CB(1) RECEPTORS IN PRIMARY SENSORY NEURONS IN NEUROPATHIC PAIN. TYPE 1 CANNABINOID RECEPTORS (CB(1)RS) ARE EXPRESSED IN THE DORSAL ROOT GANGLION (DRG) AND CONTRIBUTE TO THE ANALGESIC EFFECT OF CANNABINOIDS. HOWEVER, THE EPIGENETIC MECHANISM REGULATING THE EXPRESSION OF CB(1)RS IN NEUROPATHIC PAIN IS UNKNOWN. G9A (ENCODED BY THE EHMT2 GENE), A HISTONE 3 AT LYSINE 9 METHYLTRANSFERASE, IS A KEY CHROMATIN REGULATOR RESPONSIBLE FOR GENE SILENCING. IN THIS STUDY, WE DETERMINED G9A'S ROLE IN REGULATING CB(1)R EXPRESSION IN THE DRG AND IN CB(1)R-MEDIATED ANALGESIC EFFECTS IN AN ANIMAL MODEL OF NEUROPATHIC PAIN. WE SHOW THAT NERVE INJURY PROFOUNDLY REDUCED MRNA LEVELS OF CB(1)RS BUT INCREASED THE EXPRESSION OF CB(2) RECEPTORS IN THE RAT DRG. CHIP RESULTS INDICATED INCREASED ENRICHMENT OF HISTONE 3 AT LYSINE 9 DIMETHYLATION, A G9A-CATALYZED REPRESSIVE HISTONE MARK, AT THE PROMOTER REGIONS OF THE CB(1)R GENES. G9A INHIBITION IN NERVE-INJURED RATS NOT ONLY UP-REGULATED THE CB(1)R EXPRESSION LEVEL IN THE DRG BUT ALSO POTENTIATED THE ANALGESIC EFFECT OF A CB(1)R AGONIST ON NERVE INJURY-INDUCED PAIN HYPERSENSITIVITY. FURTHERMORE, IN MICE LACKING EHMT2 IN DRG NEURONS, NERVE INJURY FAILED TO REDUCE CB(1)R EXPRESSION IN THE DRG AND TO DECREASE THE ANALGESIC EFFECT OF THE CB(1)R AGONIST. MOREOVER, NERVE INJURY DIMINISHED THE INHIBITORY EFFECT OF THE CB(1)R AGONIST ON SYNAPTIC GLUTAMATE RELEASE FROM PRIMARY AFFERENT NERVES TO SPINAL CORD DORSAL HORN NEURONS IN WT MICE BUT NOT IN MICE LACKING EHMT2 IN DRG NEURONS. OUR FINDINGS REVEAL THAT NERVE INJURY DIMINISHES THE ANALGESIC EFFECT OF CB(1)R AGONISTS THROUGH G9A-MEDIATED CB(1)R DOWN-REGULATION IN PRIMARY SENSORY NEURONS. 2020 20 5779 25 SPINAL MICRORNA-134-5P TARGETS GLUTAMATE RECEPTOR IONOTROPIC KAINATE 3 TO MODULATE OPIOID INDUCED HYPERALGESIA IN MICE. BACKGROUND: FENTANYL AND ITS ANALOGS ARE EXTENSIVELY USED FOR PAIN RELIEF. HOWEVER, THEIR PARADOXICALLY PRONOCICEPTIVE EFFECTS OFTEN LEAD TO INCREASED OPIOIDS CONSUMPTION AND RISK OF CHRONIC PAIN. COMPARED TO OTHER SYNTHETIC OPIOIDS, REMIFENTANIL HAS BEEN STRONGLY LINKED TO ACUTE OPIOID HYPERALGESIA AFTER EXPOSURE [REMIFENTANIL-INDUCED HYPERALGESIA (RIH)]. THE EPIGENETIC REGULATION OF MICRORNAS (MIRNAS) ON TARGETED MRNAS HAS EMERGED AS AN IMPORTANT PATHOGENESIS IN PAIN. THE CURRENT RESEARCH AIMED AT EXPLORING THE SIGNIFICANCE AND CONTRIBUTIONS OF MIR-134-5P TO THE DEVELOPMENT OF RIH. METHODS: BOTH THE ANTINOCICEPTIVE AND PRONOCICEPTIVE EFFECTS OF TWO COMMONLY USED OPIOIDS WERE ASSESSED, AND MIRNA EXPRESSION PROFILES IN THE SPINAL DORSAL HORN (SDH) OF MICE ACUTELY EXPOSED TO REMIFENTANIL AND REMIFENTANIL EQUIANALGESIC DOSE (RED) SUFENTANIL WERE SCREENED. NEXT, THE CANDIDATE MIRNA LEVEL, CELLULAR DISTRIBUTION, AND FUNCTION WERE EXAMINED BY QPCR, FLUORESCENT IN SITU HYBRIDIZATION (FISH) AND ARGONAUTE-2 IMMUNOPRECIPITATION. FURTHERMORE, BIOINFORMATICS ANALYSIS, LUCIFERASE ASSAYS, MIRNA OVEREXPRESSION, BEHAVIORAL TESTS, GOLGI STAINING, ELECTRON MICROSCOPY, WHOLE-CELL PATCH-CLAMP RECORDING, AND IMMUNOBLOTTING WERE EMPLOYED TO INVESTIGATE THE POTENTIAL TARGETS AND MECHANISMS UNDERLYING RIH. RESULTS: REMIFENTANIL INDUCED SIGNIFICANT PRONOCICEPTIVE EFFECTS AND A DISTINCT MIRNA-PROFILE FROM SUFENTANIL WHEN COMPARED TO SALINE CONTROLS. AMONG TOP 30 DIFFERENTIALLY EXPRESSED MIRNAS SPECTRUM, SPINAL MIR-134-5P WAS DRAMATICALLY DOWNREGULATED IN RIH MICE BUT REMAINED COMPARATIVE IN MICE SUBJECTED TO SUFENTANIL. MOREOVER, GLUTAMATE RECEPTOR IONOTROPIC KAINATE 3 (GRIK3) WAS A TARGET OF MIR-134-5P. THE OVEREXPRESSION OF MIR-134-5P ATTENUATED THE HYPERALGESIC PHENOTYPE, EXCESSIVE DENDRITIC SPINE REMODELING, EXCITATORY SYNAPTIC STRUCTURAL PLASTICITY, AND KAINATE RECEPTOR-MEDIATED MINIATURE EXCITATORY POSTSYNAPTIC CURRENTS (MEPSCS) IN SDH RESULTING FROM REMIFENTANIL EXPOSURE. BESIDES, INTRATHECAL INJECTION OF SELECTIVE KA-R ANTAGONIST WAS ABLE TO REVERSE THE GRIK3 MEMBRANE TRAFFICKING AND RELIEVED RIH. CONCLUSION: THE MIR-134-5P CONTRIBUTES TO REMIFENTANIL-INDUCED PRONOCICEPTIVE FEATURES VIA DIRECTLY TARGETING GRIK3 TO MODULATE DENDRITIC SPINE MORPHOLOGY AND SYNAPTIC PLASTICITY IN SPINAL NEURONS. 2023